public class Exam3_6 {
	public static void main (String args [ ]) {
		double sum = 0,item = 1;
		int i = 1, n = 20;
		while (i<=n) {
			sum = sum+item;
			i=i+1;
			item = item*(1.0/i);
		}
		System.out.println("sum="+sum);
	}
}

